We have purified the antibody to rat liver alkaline phosphatase and have coupled it to sepharose. The enzyme selectively binds to columns packed with the antibody sepharose complex, and approximately 50% of the enzyme can be eluted using 1 Molar phosphate buffer, pH 11.0. We plan to use this technique to facilitate purification of rat liver alkaline phosphatase. In addition, small columns made of sepharose-antibody complex will allow us to examine many different alkaline phosphatases for immunologic relationships to rat liver alkaline phosphatase. We are currently using the above solid state antibody to measure the incorporation of H3-leucine into alkaline phosphatase following bile duct ligation.